Maine

Maine runs the largest tide range on the US East Coast and the gradient gets steeper as you move north-east up the coast toward the Bay of Fundy. Mean range at Portland is about 2.7 metres; at Bar Harbor on Mount Desert Island it is 3.1 metres; at Eastport on the Canadian border it tops 5.7. The pattern across the entire coast is cleanly semidiurnal, two highs and two lows of comparable size, twelve and a half hours apart. The funnel geometry of the broader Gulf of Maine and the Bay of Fundy approaches amplify the open-Atlantic forcing the further north-east you go. Mud-flat clamming on the Casco Bay islands, the granite-and-spruce intertidal at Acadia National Park, the working lobster fleets at Stonington and Vinalhaven, and the cliff-base beaches in Cobscook all read the table for different reasons but share the same large-amplitude signal. Nor'easter storm surge in winter can stack 30 cm or more above predicted; the harmonic predictions on this site assume normal weather. NOAA CO-OPS runs the authoritative gauge network from Portland to Eastport.